diff --git a/.vsts.pipelines/builds/matrix.yml b/.vsts.pipelines/builds/matrix.yml
index 2a7b2c52a5..fec9f74e2b 100644
--- a/.vsts.pipelines/builds/matrix.yml
+++ b/.vsts.pipelines/builds/matrix.yml
@@ -62,7 +62,7 @@ jobs:
 - template: ../jobs/ci-linux.yml
   parameters:
     job: ubuntu1804
-    imageName: mcr.microsoft.com/dotnet-buildtools/prereqs:ubuntu-18.04-f90bc20-20180320154721
+    imageName: mcr.microsoft.com/dotnet-buildtools/prereqs:ubuntu-18.04-20200918145614-047508b
 
 - template: ../jobs/ci-local.yml
   parameters:
diff --git a/.vsts.pipelines/jobs/ci-linux_bootstrap.yml b/.vsts.pipelines/jobs/ci-linux_bootstrap.yml
index 6d9dc818db..e2b59f0561 100644
--- a/.vsts.pipelines/jobs/ci-linux_bootstrap.yml
+++ b/.vsts.pipelines/jobs/ci-linux_bootstrap.yml
@@ -50,7 +50,7 @@ jobs:
       set -ex
       df -h
       $(docker.run) $(docker.bst.map) $(docker.bst.work) $(imageName) bash -c '
-      git clone --single-branch --branch pre-arcade --depth 1 https://github.com/dotnet/source-build-reference-packages'
+      git clone --single-branch --branch pre-arcade-release/3.1 --depth 1 https://github.com/dotnet/source-build-reference-packages'
       du -h $(rootDirectory) | sort -h | tail -n 50
     displayName: clone source-build-reference-packages
     condition: always()
diff --git a/NuGet.config b/NuGet.config
index 6b5910305b..d08808780d 100644
--- a/NuGet.config
+++ b/NuGet.config
@@ -3,10 +3,16 @@
   <packageSources>
     <clear />
     <!--Begin: Package sources managed by Dependency Flow automation. Do not edit the sources below.-->
+    <add key="darc-pub-dotnet-templating-7ea6e50" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-templating-7ea6e507/nuget/v3/index.json" />
+    <add key="darc-pub-dotnet-extensions-d8a50ea" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-extensions-d8a50ea1/nuget/v3/index.json" />
+    <add key="darc-pub-dotnet-core-setup-774fc3d" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-core-setup-774fc3d6/nuget/v3/index.json" />
+    <add key="darc-pub-dotnet-aspnetcore-tooling-f677187" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-aspnetcore-tooling-f6771873/nuget/v3/index.json" />
+    <add key="darc-pub-dotnet-aspnetcore-d12868d" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-aspnetcore-d12868dd/nuget/v3/index.json" />
     <!--End: Package sources managed by Dependency Flow automation. Do not edit the sources above.-->
     <add key="api.nuget.org" value="https://api.nuget.org/v3/index.json" />
     <add key="nuget-build" value="https://dotnet.myget.org/F/nuget-build/api/v3/index.json" />
     <add key="arcade" value="https://dotnetfeed.blob.core.windows.net/dotnet-tools-internal/index.json" />
     <add key="dotnet-core" value="https://dotnetfeed.blob.core.windows.net/dotnet-core/index.json" />
   </packageSources>
+  <disabledPackageSources />
 </configuration>
diff --git a/eng/SourceBuild.Tarball.targets b/eng/SourceBuild.Tarball.targets
index 337695f179..a3211831e7 100644
--- a/eng/SourceBuild.Tarball.targets
+++ b/eng/SourceBuild.Tarball.targets
@@ -25,6 +25,8 @@
     Project="SourceBuild.Tarball.DestructiveCleanup.targets"
     Condition="'$(DestructiveIntermediateClean)' == 'true'"/>
 
+  <UsingTask AssemblyFile="$(XPlatSourceBuildTasksAssembly)" TaskName="RemoveInternetSourcesFromNuGetConfig" />
+
   <Target Name="GetTarballDirProps">
     <PropertyGroup>
       <TarballRootDir>$([MSBuild]::NormalizeDirectory('$(TarballRoot)'))</TarballRootDir>
@@ -151,23 +153,39 @@
         Include="$(ProjectDir)support/tarball/build.sh"
         RelativeDestination="build.sh" />
 
-      <!--
-        When building an internal build, the main smoke-test nuget config has authenticated sources
-        in it to generate a full set of smoke-test-prereqs. This isn't necessary in the tarball
-        because we have those smoke-test-prereqs, but we hit authentication errors nonetheless. Copy
-        a trimmed down nuget.config in this case.
-        TODO: Automatically trim down the main nuget.config.
-      -->
-      <TarballCopyFile
-        Condition="Exists('$(ProjectDir)support\tarball\smoke-testNuGet.Config')"
-        Include="$(ProjectDir)support\tarball\smoke-testNuGet.Config"
-        RelativeDestination="smoke-testNuGet.Config" />
-
       <!-- Setup package version props to include both source-built and running PackageVersions.props -->
       <TarballCopyFile
         Include="$(ProjectDir)support\tarball\PackageVersions.props"
         RelativeRoot="artifacts/obj/$(Platform)/Release/" />
     </ItemGroup>
+
+    <!--
+      When building an internal build, the main smoke-test nuget config has authenticated sources in
+      it to generate a full set of smoke-test-prereqs. We need to get rid of these internal feeds in
+      the tarball to avoid hitting authentication errors. (In the tarball, we have those
+      smoke-test-prereqs in a local feed, so this is fine.)
+
+      Use the nuget trimming task to create a tarball nuget.config without the internal feeds, for
+      this case. Importantly, this leaves public feeds alone: when running a public servicing build,
+      we need to use them for runtime packs, and the smoke-test-prereqs tarball won't contain them.
+    -->
+    <PropertyGroup>
+      <FilteredSmokeTestNuGetConfig>$(ArtifactsDir)support\smoke-testNuGet.Config</FilteredSmokeTestNuGetConfig>
+    </PropertyGroup>
+
+    <Copy
+      SourceFiles="$(ProjectDir)smoke-testNuGet.Config"
+      DestinationFiles="$(FilteredSmokeTestNuGetConfig)" />
+
+    <RemoveInternetSourcesFromNuGetConfig
+      NuGetConfigFile="$(FilteredSmokeTestNuGetConfig)"
+      OfflineBuild="false" />
+
+    <ItemGroup>
+      <TarballCopyFile
+        Include="$(FilteredSmokeTestNuGetConfig)"
+        RelativeDestination="smoke-testNuGet.Config" />
+    </ItemGroup>
   </Target>
 
   <Target Name="AddTarballPackages">
diff --git a/eng/Version.Details.xml b/eng/Version.Details.xml
index f421a7707f..6a7280b214 100644
--- a/eng/Version.Details.xml
+++ b/eng/Version.Details.xml
@@ -27,9 +27,9 @@
       <Sha>1127689f262d52ea8ff68ef03d706fa62b3b40a1</Sha>
       <RepoName>linker</RepoName>
     </Dependency>
-    <Dependency Name="Microsoft.NETCore.Runtime.CoreCLR" Version="3.1.8-servicing.20411.5" CoherentParentDependency="Microsoft.Private.CoreFx.NETCoreApp">
+    <Dependency Name="Microsoft.NETCore.Runtime.CoreCLR" Version="3.1.9-servicing.20472.1" CoherentParentDependency="Microsoft.Private.CoreFx.NETCoreApp">
       <Uri>https://github.com/dotnet/coreclr</Uri>
-      <Sha>f897710bc4efe6a046068fde0acf641667a8fff5</Sha>
+      <Sha>8775efa17eaf06dc8b6ea9dd3917871fe2d7ff8e</Sha>
       <RepoName>coreclr</RepoName>
       <RepoName>coreclr-portable</RepoName>
     </Dependency>
@@ -37,26 +37,26 @@
       <Uri>https://github.com/dotnet/standard</Uri>
       <Sha>a5b5f2e1e369972c8ff1e2183979fab6099f52ef</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Private.CoreFx.NETCoreApp" Version="4.7.0-servicing.20419.3" CoherentParentDependency="Microsoft.NETCore.App.Runtime.linux-x64">
+    <Dependency Name="Microsoft.Private.CoreFx.NETCoreApp" Version="4.7.0-servicing.20472.3" CoherentParentDependency="Microsoft.NETCore.App.Runtime.linux-x64">
       <Uri>https://github.com/dotnet/corefx</Uri>
-      <Sha>d6302a72f8eafa326d7572a02acf8f3021ebb9e8</Sha>
+      <Sha>3009a1fc20d9cb47d117399040d31c23f7b23e02</Sha>
       <RepoName>corefx</RepoName>
       <RepoName>corefx-portable</RepoName>
     </Dependency>
-    <Dependency Name="Microsoft.NETCore.App.Runtime.linux-x64" Version="3.1.8" CoherentParentDependency="Microsoft.Dotnet.Sdk.Internal">
+    <Dependency Name="Microsoft.NETCore.App.Runtime.linux-x64" Version="3.1.9" CoherentParentDependency="Microsoft.Dotnet.Sdk.Internal">
       <Uri>https://github.com/dotnet/core-setup</Uri>
-      <Sha>9c1330deddc14e8c564e30402d6a644c43110778</Sha>
+      <Sha>774fc3d6a9659077864171d095f46b1ea19bb51d</Sha>
       <RepoName>core-setup</RepoName>
       <RepoName>core-setup-portable</RepoName>
     </Dependency>
-    <Dependency Name="Microsoft.AspNetCore.Mvc.Razor.Extensions" Version="3.1.8" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.linux-x64">
+    <Dependency Name="Microsoft.AspNetCore.Mvc.Razor.Extensions" Version="3.1.9" CoherentParentDependency="Microsoft.AspNetCore.App.Runtime.linux-x64">
       <Uri>https://github.com/dotnet/aspnetcore-tooling</Uri>
-      <Sha>02423c0c6c445b12abea9fee03ebdb2e18b4a2dd</Sha>
+      <Sha>f677187340747f56193e7731df449579b4ba5af6</Sha>
       <RepoName>aspnetcore-tooling</RepoName>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Common.ItemTemplates" Version="3.1.8" CoherentParentDependency="Microsoft.Dotnet.Sdk.Internal">
+    <Dependency Name="Microsoft.DotNet.Common.ItemTemplates" Version="3.1.9" CoherentParentDependency="Microsoft.Dotnet.Sdk.Internal">
       <Uri>https://github.com/dotnet/templating</Uri>
-      <Sha>10dad0fa67c3cd3db542c29d591de026ed45147b</Sha>
+      <Sha>7ea6e5075b24adc5a0d8964125699d141ac67efa</Sha>
       <RepoName>templating</RepoName>
     </Dependency>
     <Dependency Name="Microsoft.NETCore.Compilers" Version="3.4.1-beta4-20127-10" CoherentParentDependency="Microsoft.Dotnet.Toolset.Internal">
@@ -72,14 +72,14 @@
       <Sha>6f8eb3a2e1db6b458451b9cfd2a4f5557769b041</Sha>
       <RepoName>nuget-client</RepoName>
     </Dependency>
-    <Dependency Name="Microsoft.Extensions.Logging" Version="3.1.8" CoherentParentDependency="Microsoft.AspNetCore.Mvc.Razor.Extensions">
+    <Dependency Name="Microsoft.Extensions.Logging" Version="3.1.9" CoherentParentDependency="Microsoft.AspNetCore.Mvc.Razor.Extensions">
       <Uri>https://github.com/dotnet/extensions</Uri>
-      <Sha>1774c15ac24c65513fa9fc1f4fbb69be9a2a4e25</Sha>
+      <Sha>d8a50ea1cc9892cda13c5237dec402ca10ddeaa1</Sha>
       <RepoName>aspnet-extensions</RepoName>
     </Dependency>
-    <Dependency Name="Microsoft.NET.Sdk" Version="3.1.108-servicing.20413.3" CoherentParentDependency="Microsoft.Dotnet.Toolset.Internal">
+    <Dependency Name="Microsoft.NET.Sdk" Version="3.1.109-servicing.20461.11" CoherentParentDependency="Microsoft.Dotnet.Toolset.Internal">
       <Uri>https://github.com/dotnet/sdk</Uri>
-      <Sha>82e2b68c9ef7f28307114c4ab4d43c11e6f7cd52</Sha>
+      <Sha>afdde814dc8dedb325e63b39cf72249b43918a23</Sha>
       <RepoName>sdk</RepoName>
     </Dependency>
     <Dependency Name="Microsoft.DotNet.Cli.CommandLine" Version="1.0.0-preview.19208.1" CoherentParentDependency="Microsoft.DotNet.Cli.Runtime">
@@ -96,37 +96,37 @@
       <Uri>https://github.com/dotnet/xliff-tasks</Uri>
       <Sha>173ee3bd61c9549557eefa3cfb718bdef157cb87</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.AspNetCore.App.Runtime.linux-x64" Version="3.1.8" CoherentParentDependency="Microsoft.Dotnet.Sdk.Internal">
+    <Dependency Name="Microsoft.AspNetCore.App.Runtime.linux-x64" Version="3.1.9" CoherentParentDependency="Microsoft.Dotnet.Sdk.Internal">
       <Uri>https://github.com/dotnet/aspnetcore</Uri>
-      <Sha>c75b3f7a2fb9fe21fd96c93c070fdfa88a2fbe97</Sha>
+      <Sha>d12868dd7c10ff0433c16b06d3b59d03c40d987a</Sha>
       <RepoName>aspnetcore</RepoName>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Cli.Runtime" Version="3.1.108-servicing.20422.1" CoherentParentDependency="Microsoft.Dotnet.Toolset.Internal">
+    <Dependency Name="Microsoft.DotNet.Cli.Runtime" Version="3.1.109-servicing.20473.6" CoherentParentDependency="Microsoft.Dotnet.Toolset.Internal">
       <Uri>https://github.com/dotnet/cli</Uri>
-      <Sha>781686b7534a8203e3944c2b111df5a279d9c43e</Sha>
+      <Sha>8425963d35b2ebb92fdb4312e20ce3f91a886073</Sha>
       <RepoName>cli</RepoName>
     </Dependency>
     <Dependency Name="Microsoft.FSharp.Compiler" Version="10.7.0-beta.19610.6" CoherentParentDependency="Microsoft.Dotnet.Toolset.Internal">
       <Uri>https://github.com/dotnet/fsharp</Uri>
       <Sha>dc86ab5d2c46e9a7c49290e7e2270ab1eeb0c61e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.NET.Sdk.Web" Version="3.1.108-servicing.20421.3" CoherentParentDependency="Microsoft.Dotnet.Toolset.Internal">
+    <Dependency Name="Microsoft.NET.Sdk.Web" Version="3.1.109-servicing.20473.3" CoherentParentDependency="Microsoft.Dotnet.Toolset.Internal">
       <Uri>https://github.com/dotnet/websdk</Uri>
-      <Sha>3478a1379fe3765b28eb3f7cb889fb45233fb09c</Sha>
+      <Sha>d4160cb5bf36df284208df3f64c7a461826eb90d</Sha>
       <RepoName>websdk</RepoName>
     </Dependency>
     <Dependency Name="Microsoft.NET.Test.Sdk" Version="16.3.0" CoherentParentDependency="Microsoft.Dotnet.Toolset.Internal">
       <Uri>https://github.com/microsoft/vstest</Uri>
       <Sha>55e7e45431c9c05656c999b902686e7402664573</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Dotnet.Toolset.Internal" Version="3.1.108-servicing.20422.1" CoherentParentDependency="Microsoft.Dotnet.Sdk.Internal">
+    <Dependency Name="Microsoft.Dotnet.Toolset.Internal" Version="3.1.109-servicing.20473.11" CoherentParentDependency="Microsoft.Dotnet.Sdk.Internal">
       <Uri>https://github.com/dotnet/toolset</Uri>
-      <Sha>d04a69c978e9099d743ce68c667fafe9a1a7d59e</Sha>
+      <Sha>6bde7fd6666a4e97f5409b536ff5290bcb3bcd3e</Sha>
       <RepoName>toolset</RepoName>
     </Dependency>
-    <Dependency Name="Microsoft.Dotnet.Sdk.Internal" Version="1.0.0-preview.20422.8">
+    <Dependency Name="Microsoft.Dotnet.Sdk.Internal" Version="1.0.0-preview.20474.6">
       <Uri>https://github.com/dotnet/installer</Uri>
-      <Sha>c423b556b530ff8a168386d63821acb6dfc6ee5d</Sha>
+      <Sha>32ced2d411573dd57d75c222e5d89ecd0e03c11d</Sha>
       <RepoName>core-sdk</RepoName>
     </Dependency>
     <!-- external dependencies, not handled by Maestro/Arcade -->
diff --git a/eng/Versions.props b/eng/Versions.props
index f9bd6bbda2..313c71a8c1 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -8,6 +8,6 @@
   <!-- Production Dependencies -->
   <PropertyGroup>
     <PrivateSourceBuildReferencePackagesPackageVersion>1.0.0-beta.20374.1</PrivateSourceBuildReferencePackagesPackageVersion>
-    <PrivateSourceBuiltArtifactsPackageVersion>0.1.0-3.1.106</PrivateSourceBuiltArtifactsPackageVersion>
+    <PrivateSourceBuiltArtifactsPackageVersion>0.1.0-3.1.108</PrivateSourceBuiltArtifactsPackageVersion>
   </PropertyGroup>
 </Project>
diff --git a/global.json b/global.json
index b2a5c98255..46ef012170 100644
--- a/global.json
+++ b/global.json
@@ -1,6 +1,6 @@
 {
   "tools": {
-    "dotnet": "3.1.106"
+    "dotnet": "3.1.108"
   },
   "msbuild-sdks": {
     "Microsoft.Build.CentralPackageVersions": "2.0.1",
diff --git a/smoke-testNuGet.Config b/smoke-testNuGet.Config
index afbad0b55e..2240197196 100644
--- a/smoke-testNuGet.Config
+++ b/smoke-testNuGet.Config
@@ -4,6 +4,11 @@
     <!--To inherit the global NuGet package sources remove the <clear/> line below -->
     <clear />
     <!--Begin: Package sources managed by Dependency Flow automation. Do not edit the sources below.-->
+    <add key="darc-pub-dotnet-templating-7ea6e50" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-templating-7ea6e507/nuget/v3/index.json" />
+    <add key="darc-pub-dotnet-extensions-d8a50ea" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-extensions-d8a50ea1/nuget/v3/index.json" />
+    <add key="darc-pub-dotnet-core-setup-774fc3d" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-core-setup-774fc3d6/nuget/v3/index.json" />
+    <add key="darc-pub-dotnet-aspnetcore-tooling-f677187" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-aspnetcore-tooling-f6771873/nuget/v3/index.json" />
+    <add key="darc-pub-dotnet-aspnetcore-d12868d" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-aspnetcore-d12868dd/nuget/v3/index.json" />
     <!--End: Package sources managed by Dependency Flow automation. Do not edit the sources above.-->
     <add key="source-built-packages" value="SOURCE_BUILT_PACKAGES" />
     <add key="api.nuget.org" value="https://api.nuget.org/v3/index.json" />
diff --git a/support/tarball/smoke-testNuGet.Config b/support/tarball/smoke-testNuGet.Config
deleted file mode 100644
index afbad0b55e..0000000000
--- a/support/tarball/smoke-testNuGet.Config
+++ /dev/null
@@ -1,14 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<configuration>
-  <packageSources>
-    <!--To inherit the global NuGet package sources remove the <clear/> line below -->
-    <clear />
-    <!--Begin: Package sources managed by Dependency Flow automation. Do not edit the sources below.-->
-    <!--End: Package sources managed by Dependency Flow automation. Do not edit the sources above.-->
-    <add key="source-built-packages" value="SOURCE_BUILT_PACKAGES" />
-    <add key="api.nuget.org" value="https://api.nuget.org/v3/index.json" />
-    <add key="dotnet-core" value="https://dotnetfeed.blob.core.windows.net/dotnet-core/index.json" />
-    <add key="ProdCon" value="PRODUCT_CONTRUCTION_PACKAGES" />
-    <add key="smoke-test feed" value="SMOKE_TEST_PACKAGE_FEED" />
-  </packageSources>
-</configuration>
diff --git a/tools-local/prebuilt-baseline-online.xml b/tools-local/prebuilt-baseline-online.xml
index db3d90aba2..a964d39fea 100644
--- a/tools-local/prebuilt-baseline-online.xml
+++ b/tools-local/prebuilt-baseline-online.xml
@@ -6,7 +6,9 @@
     <UsagePattern IdentityGlob="Microsoft.DotNet.Web.ProjectTemplates.3.1/3.1.*" />
     <UsagePattern IdentityGlob="Microsoft.DotNet.Web.Spa.ProjectTemplates.3.1/3.1.*" />
     <UsagePattern IdentityGlob="Microsoft.Dotnet.WinForms.ProjectTemplates/3.1.*" />
+    <UsagePattern IdentityGlob="Microsoft.Dotnet.WinForms.ProjectTemplates/4.8.*" />
     <UsagePattern IdentityGlob="Microsoft.DotNet.Wpf.ProjectTemplates/3.1.*" />
+    <UsagePattern IdentityGlob="Microsoft.NETCore.Platforms/3.1.0*" />
   </IgnorePatterns>
   <Usages>
     <Usage Id="MicroBuild.Core" Version="0.2.0" IsDirectDependency="true" IsAutoReferenced="true" />
@@ -52,8 +54,6 @@
     <Usage Id="Microsoft.DotNet.Web.Spa.ProjectTemplates.2.1" Version="2.1.14" />
     <Usage Id="Microsoft.DotNet.Web.Spa.ProjectTemplates.2.2" Version="2.2.8" />
     <Usage Id="Microsoft.DotNet.Web.Spa.ProjectTemplates.3.0" Version="3.0.1" />
-    <Usage Id="Microsoft.Dotnet.WinForms.ProjectTemplates" Version="4.8.0-rc2.19462.10" />
-    <Usage Id="Microsoft.Dotnet.WinForms.ProjectTemplates" Version="4.8.1-servicing.20412.5" />
     <Usage Id="Microsoft.DotNet.Wpf.ProjectTemplates" Version="3.0.0" />
     <Usage Id="Microsoft.Extensions.DependencyModel" Version="2.1.0" IsDirectDependency="true" />
     <Usage Id="Microsoft.NETCore.App" Version="2.0.0" IsDirectDependency="true" IsAutoReferenced="true" />
@@ -77,7 +77,6 @@
     <Usage Id="Microsoft.NETCore.Platforms" Version="2.1.0" />
     <Usage Id="Microsoft.NETCore.Platforms" Version="2.1.2" />
     <Usage Id="Microsoft.NETCore.Platforms" Version="3.0.0-preview9.19409.15" IsDirectDependency="true" />
-    <Usage Id="Microsoft.NETCore.Platforms" Version="3.1.0-preview3.19551.4" IsDirectDependency="true" />
     <Usage Id="Microsoft.NETCore.Targets" Version="1.0.1" />
     <Usage Id="Microsoft.NETCore.Targets" Version="1.1.0" />
     <Usage Id="Microsoft.NETCore.Targets" Version="2.1.0" />